This invention relates to a piston-type passenger conveying system wherein elevator cabs are moved to be out of phase from each other and to move passengers between two floors continuously.
Typically, passengers are moved between the floors in low rise buildings such as malls, etc. by escalators. Escalators are widely utilized in most malls, although malls typically incorporate a few elevators. Known elevators dispatch cabs based upon a passenger call or request for a cab. The elevators do not move as many passengers as quickly as an escalator due to wait time, door opening time, dwell time, etc. Shoppers in a mall seem to prefer the escalators in that they move more quickly between the floors, and the movement is continuous without wait time. Also, shoppers may like the open nature of escalators as they can look around the mall.
Statistics show that an average escalator moves a much higher number of passengers than the elevators in such locations. However, escalators do have down sides. As examples, escalators do not move strollers, wheelchairs, etc. as well as do elevators.
It is thus the goal of this invention to propose an elevator-like system that has continuous flow of passengers like an escalator.
In disclosed embodiments of this invention, at least three elevator cabs are operated such that they are maintained out of phase from each other for movement between two floors. For purposes of this Application, the term xe2x80x9cout of phasexe2x80x9d used for the position of the cabs can be understood by first defining a cycle of movement. In normal operation, a control moves a plurality of cabs through a desired cycle of movement. The cycle of movement could be described as starting when a cab initially reaches a floor, then moves away to another floor, and eventually returns to the first floor. For purposes of this invention, the several cabs are maintained such that they are at different points in this cycle at different times relative to each other. In this sense they are xe2x80x9cout of phasexe2x80x9d. The cycle of movement can be described as 360xc2x0, and thus three cabs are maintained 120xc2x0 out of phase, four cabs are maintained 90xc2x0 out of phase, etc. In one main aspect of this invention, a control system moves a plurality of elevator cabs based upon a cyclically changing desired position. Typically, cabs are moved to respond to a passenger call or request. The present invention discloses a system which control movement based solely on moving the cabs to a desired position such that there will be a cab at each floor at all times when the system is operating under normal conditions.
In a preferred embodiment, there are four cabs grouped into two pairs, with each of the two in a pair being maintained 180xc2x0 out of phase from each other, and offset by 90xc2x0 from the other pair. A control tries to maintain a cab always open at each of the two floors. Another cab is always moving toward each floor. For purposes of this application, the description xe2x80x9cmoving toward the other floorxe2x80x9d would include the door opening time, etc. after arrival at the floor.
In the actual physical systems according to this invention, it may be that a cab will actually arrive at the floor to which it is heading before the cab at that floor leaves. Thus, for purposes of this Application, the invention is disclosed as having a cab usually moving to one of the floors, and one cab usually waiting at each of the floors. Further, it should be understood that the above-described control is under normal conditions. There may be other conditions such as a sleep mode, or a mode which is entered under particular periods of time, wherein this basic control is not operational. As one example only, in a system in a mall, it may be that the cabs are all generally moved to the first floor when the mall opens. However, under normal conditions, the above-discussed control will be in place.
Further, other numbers of cabs beyond four can be utilized. The system can operate with any number of cabs greater than two. Further, more than two pairs may be utilized. While several distinct numbers of cabs are disclosed, it should be understood that the main features of this invention can be achieved by any number of cabs greater than two.
In a preferred embodiment of this invention, the two cabs in the pair are driven by a single machine through a rope or cable. Preferred methods of moving the cab pairs are also disclosed.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.